But helping other people often brings happiness on its own.
I helped because I could and I wanted to. It makes me happy to help other people. Happy is a loaded word anyway. What is happiness? Some bits of chemicals in our brain? I have trained my reward function to be happy for something it gets no real material or survival benefit from. Maybe it thinks it is getting some benefit in my default mode network. I help people and they will help me? I am sure the DMN sets forth that narrative at some level. But there is a deeper trick to all of it in which I know there is often no survival or conscious narrative benefit. I just did a pro social human thing. Maybe the hormones that generates are enough to convince my DMN to keep doing it? Maybe if you wire your empathy centers deeply enough to experience things through other people you can convince your DMN it is valuable. IDK how it works, I do meditate on it. But mostly it is just about connection and helping people on their journey through life as countless others have helped me. I figure if I end it with having helped others more than I was helped that's a pretty good score. Sort of like the seinfeld quote about driving a porsche: Having the lowest mileage Porsche when reaching heaven signifies a failure to enjoy life, which is considered one of life's greatest sins?
something like that maybe? Who knows. I am going to keep putting help others mileage out there until my time is up, I am very fortunate in this life.
We live in industrialized society, it is highly dependent on a vast ecosystem of other humans doing specialized jobs. To have a genuine interest you just decide to have one. Why do people choose the hobbies they do. Why this software project over that one. Why do some people like this car or that other car. What motivates people. If you ask people will almost universally be happy to tell you about things they care about. You don't need any particular reason. The fact that you are on HN indicates you at least nominally are interested in others.
I think some rare people genuinely are just happier off in a cabin in the woods, mostly independent of other humans, but we are generally not evolved that way. We simply have a vast amount of chemical and mental machinery dedicated to experiencing life as a social construct and system. Also, having friends to avoid loneliness is that exact machinery we evolved. It isn't required in any logical sense, but in a very real physical sense our bodies and minds reward us for socializing.